Misestimating the number of staff required is one of the most common and costly operational mistakes. Too few means poor service and an exhausted team. Too many means unjustified costs. The right methodology produces an accurate estimate that achieves balance.
Why Is Accurate Estimation Necessary?
- For negotiation: An accurate number makes your negotiation with the supply company stronger
- For the budget: Correct financial planning without surprises
- For quality: A sufficient number means a sustainable service
- For the relationship with the provider: Clear expectations build a successful relationship
The Steps to Determining the Required Number
Step 1: Inventory the complete tasks
A comprehensive list of everything the site needs:
- What services are required? (cleaning, maintenance, operation, security, services)
- Which areas need coverage?
- What working hours are required?
- Are there daily tasks and others that are periodic?
Step 2: Estimate the time for each task
For each task, estimate:
| Task | Estimated time | Frequency | Daily total |
|---|---|---|---|
| Sweeping and mopping 500 m² of corridor | 45 minutes | Twice daily | 90 minutes |
| Cleaning a restroom | 20 minutes | 3 times daily | 60 minutes |
| Cleaning a 20 m² office | 10 minutes | Once daily | 10 minutes |
| Removing trash (20 bins) | 30 minutes | Twice daily | 60 minutes |
Step 3: Calculate the total daily time
Sum the times of all tasks to get the total minutes required daily.
📌 Example: A site needs 960 minutes of work daily. An 8-hour shift = 480 actual minutes per worker (after deducting breaks). So: 960 ÷ 480 = 2 workers.
Step 4: Add adjustment factors
| The factor | Adjustment factor | Application |
|---|---|---|
| An expected absence rate of 10% | × 1.1 | Absence reserve |
| Transit time between areas | × 1.1 | For large sites |
| Break periods (15% of the time) | Deducted from the available time | Accounted for in Step 3 |
| Irregular tasks and emergencies | + 10% of the total | Emergency margin |
Step 5: Estimate the number of supervisors
The supervisor ratio depends on the type of service:
- Cleaning: 1 supervisor per 12–18 workers
- Maintenance: 1 supervisor per 8–12 technicians
- General operation: 1 supervisor per 15–20 workers
A Full Calculation Example for a Real Site
Site: A 3,000 m² commercial complex with 6 restrooms, operating 12 hours daily
The daily tasks and their times
| Task | Total time daily |
|---|---|
| Corridor cleaning (3,000 m² × twice) | 240 minutes |
| Restrooms (6 × 3 times × 20 minutes) | 360 minutes |
| Lobby and entrances (continuous) | 120 minutes |
| Removing trash | 90 minutes |
| Emergencies and immediate spills | 60 minutes |
| The total | 870 minutes |
The calculation
- The worker's actual time in an 8-hour shift: 480 minutes × 85% = 408 minutes
- The base number of workers: 870 ÷ 408 = 2.13 → 3 workers
- Adjusting for absence and emergencies: 3 × 1.15 = 3.45 → 4 workers
- For 12 hours (one and a half shifts): 4 × 1.5 = 6 workers
- Supervisor: 1 per 15 = 1 supervisor
- The total: 6 workers + 1 supervisor = 7 staff
💡 Verify the number: Before relying on your calculation, ask the supply company for its opinion on the number after a site visit. A site visit produces a more accurate estimate than a theoretical calculation.
Factors That Change the Calculated Number
- Seasons and peaks: Ramadan and Eid need 30–50% more
- Special events: Need temporary additional staff
- Changing the site's activity: Opening a new section or closing one
- Changing working hours: Expanding to 24 hours doubles the need
Conclusion
Determining the number of staff is a methodology, not a guess. Start by inventorying the tasks and their times, calculate the total, add adjustment factors, and verify the result with a company that has field experience. The right number saves costs and raises quality at the same time.
Frequently Asked Questions
Yes, this is a practical approach especially for new sites. Start with the sufficient minimum and adjust the number after two to three weeks of actual operation.
Calculate the need for each shift separately, then sum. Shifts aren't equal — the daytime peak needs more than the night shift at most sites.
The theoretical calculation is a good starting point, but a site visit is necessary to get an accurate number. The actual distances, the nature of the floors, and the distribution of restrooms — all are details that don't appear in theoretical numbers.